Comparison of sperm concentration in fresh and postal post-vasectomy semen samples: a prospective agreement study

We analysed the results of 197 paired PVSA. The Bland-Altman plot showed high agreement between fresh and postal sperm concentrations, with only seven samples outlying 95% CIs. Fresh PVSA sperm concentrations were classified higher than postal in 47 (22.1%) pairs and lower in 42 (19.8%). Most discrepancies were observed at sperm concentrations <1000 sperm/mL. 'No sperm seen' was reported in 86 (43.7%) pairs with false negatives encountered in both laboratories (McNemar's test p=0.045). Negative predictive values of postal compared with fresh results were >99% at all cut-off values from 1000 to 100 000 sperm/mL CONCLUSION: Our study showed high agreement in sperm concentrations of first PVSA performed on the same samples submitted fresh or by postal submission. The current postal testing strategy could be modified to encompass clearance on postal PVSA showing very low sperm concentrations.